Process of making light-transforming compositions.



UNITED STATES PATENT OFFICE.-

PETEB COOPER HEWITT, OE BINGWOOD MANOR, NEW JERSEY, ASSIGNOR TO COOPER Y OF HOBOKEN, NEW JERSEY, A CORPORATION OF HEWITT ELECTRIC COMPANY, NEW JERSEY.

No Drawing. Original application filed July 23, 1919, Serial No. 573,557. Divided and filed October 20, 1918. Serial No. 796,166.

To all whom it may concern Be it known that 1, PETER Goorniz; citizen of the United States, and resident of Ringwood Manor, county of Passaic, State of New Jersey, have invented certain new and useful Improvements in Processes of Making Light-Transforming Compositions, of which the following is a specification. I

My invention relatesto the class of devices employed for combining rays of a source of light which is deficient in some desired portion oft-he spectrum with rays of other wave length produced by the transformation of certainrays or waves of one length into rays or waves of another length and of such character as to supply the ray or wave length desired, within limits.

Ina patent issued to me on 1908, bearing No. 907,598 and in a companion application Serial No. 453,187, filed by me September 15, 1908, I have described certain methods of producing and utilizing light rays of the character referred to, and

my present invention relates more particularly to special compounds of materials to be used for transforming 'light rays and,

when desired, adding light waves of definite character to light from any source.

Retentiveness of the fluorescent quality,

or durability of the-property of transform ing' light, seems from experiment to be seriously modified by the internal structure or .physical arrangement of the material in its final state. That is, the material retains this light transforming property better and for a longer period by 'reason of. its being or having been m a state of internal stress or by reason of the fact that the internal 40 structure is fibrous in nature. It is important also that the conditions of drying or carried. out, as affecting the physical relation of the materials to each other during 4 5 manufacturing and as affecting the finished product.

In practical. find that, while-several different materials and compounds -may be used with greater or less efliciency and du- 60 rability or retentiveness, most excellent results are obtained by the use of rhodamin combined in proper proportions withacetate of celluloseto which glycerin has December 22,

hardeningof the material be properly PROCESS OF MAKDIG LIGHT-TBLN SFOBIuING COMPOSITIONS.-

Patented June 27, 1916.- this application been added. A combination or association of the materials, having a structure retentive of the'light transforming pro erty under conditions of good efliciency ans durabllity, can be secured in the foregoing manner. 1

A varnish formed consisting of 70% {of acetate of cellulose;'10% of glycerin and 20% of acetlc acid, the above percentages being the percentages by-weight. To this is added technical acetone to make a 12% solution.

The acetate of cellulose, known in commerce as cellet may be used and prepared as follows: Itmay be first bleached'with-permanganate of potash made acid with sul-, furic acid, and subsequently treated with sulfurous acid for further bleaching and removing the permanganate, and washed with wateruntil free from salts. An amount of rhodamin, equivalent to three one-hum.

dredths by weight of the weight of cellet and glycerin is added, the rhodamin being in solut1on in alcohol or acetone for convenience. The whole .forms a varnish which when dry may be used either for reflecting purposes or as'a light screen or filter, that is to say, it may be painted upon a smtable backing and when dry the transformed light reflected therefrom and mingled with the lightfrom the source, or it may be made into a film or painted upon a proper transparent backing and placed wholly or partially' aroundthe source of light so that p more or-less of the original light and the transformed light will be mingled.

In an application 18, 1909 Serial Number 518,325, I vhave described various forms of backings or sup filed by me September ports for varnishes of this general character and also materials which-may be mixed with. the varnish for the purpose of increasing the light qualities thereof. When it is to be placed upon a backing or en port to serve as a light reflector, I have ound it advantageous to use as the immediate support .for the varnish a material, such for instance, as calcimine or white lead, or other material having the characteristics of dispersing light. In some desired to mix the light-dispersing material with the'varnish. V

The proportions above given may be instances it may be a i modified to a reasonable degree, but those given above are found to produce a material having efliciency and durability combined.

In the drying of the material, the acetic acid and acetone evaporate, leaving the acetate of cellulose, the coloring matter, and

an amount of glycerin asthe light transformer.

The varnish may be painted upon a suitable temporary support and driedand then stripped ofi from the support and used in-' dependently of any other support as light reflector or screen. 7

Any desired number of coatings of the varnish may be painted upon the support in succession. I have found, for instance, that five coats quickly flowed, one after the other, gives a very eflicient result;

This application is a division of my apthe pl'ication filed July 23rd, 1910, Serial Number 573,557.

I claim as my invention: The process of manufacturing light transforming compositions, having a structure retentive of light transforming 'property which consists in mixing, substantially in the proportions described cellet, glycerin, acetic acid and rhodamin with technical acetone sufiicient to make the resulting solution contain approximately 12 per cent. of acetone and drying the same, thereby leaving cellet, rhodamin and glycerin.

Signed at New York .in the county of New York and State of New York this 16th day of October A. D. 1913.

PETER COOPER HEWITT.

Witnesses:

Wu. H. GAPEL,

THos. H. Bnowru 

